Helleborus plant named ‘COSEH 960’

ABSTRACT

A new and distinct cultivar of  Helleborus  plant named ‘COSEH 960’, characterized by its upright and mounded plant habit; uniform and freely flowering habit; dark green-colored leaves; long flowering period; single white-colored flowers; and good garden performance.

Botanical designation: Helleborus niger×Helleborus hybridus.

Cultivar denomination: ‘COSEH 960’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Helleborus plant, botanically known as Helleborus niger×Helleborus hybridus, and hereinafter referred to by the name ‘COSEH 960’.

The new Helleborus plant is a product of a planned breeding program in Glandorf, Germany. The objective of the breeding program was to create new uniform Helleborus plants with unique and attractive plant habit, leaf and flower coloration and resistance to pests.

The new Helleborus plant originated from a cross-pollination conducted by the Inventor in Glandorf, Germany in December, 2005 of an unnamed proprietary seedling selection of Helleborus niger, not patented, as the female, or seed, parent with an unnamed proprietary seedling selection of Helleborus hybridus, not patented, as the male, or pollen, parent. The new Helleborus plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination grown in a controlled greenhouse environment in Glandorf, Germany in January, 2008.

Asexual reproduction of the new Helleborus plant by divisions in a controlled greenhouse environment in Glandorf, Germany since March, 2008 has shown that the unique features of this new Helleborus plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Helleborus have not been observed under all possible environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘COSEH 960’. These characteristics in combination distinguish ‘COSEH 960’ as a new and distinct Helleborus plant:

-   -   1. Upright and mounded plant habit.     -   2. Uniform and freely flowering habit.     -   3. Dark green-colored leaves.     -   4. Long flowering period.     -   5. Single white-colored flowers.     -   6. Good garden performance.

Compared to plants of the parent selections, plants of the new Helleborus are more uniformly mounded and are more freely flowering.

Plants of the new Helleborus can be compared to plants of Helleborus niger×Helleborus hybridus ‘COSEH 710’, disclosed in U.S. Plant Pat. No. 21,063. In side-by-side comparisons conducted in Glandorf, Germany, plants of the new Helleborus differed from plants of ‘COSEH 710’ in leaf and flower color.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the overall appearance of the new Helleborus plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Helleborus plant.

The photograph on the first sheet comprises a side perspective view of a typical flowering plant of ‘COSEH 960’ grown in a container.

The photograph on the second sheet is a close-up view of a typical flower of ‘COSEH 960’.

DETAILED BOTANICAL DESCRIPTION

The aforementioned photographs and following observations, measurements and values describe plants grown during the winter in 17-cm containers in a glass-covered greenhouse in Glandorf, Germany and under environmental conditions and cultural practices which closely approximate commercial Helleborus production. During the production of the plants, day temperatures ranged from 12° C. to 32° C. and night temperatures ranged from 3° C. to 18° C. Plants were 14 months old when the photographs and the description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2007 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical classification: Helleborus niger×Helleborus hybridus     ‘COSEH 960’. -   Parentage:     -   -   Female, or seed, parent.—Unnamed proprietary seedling             selection of Helleborus niger, not patented.         -   Male, or pollen, parent.—Unnamed proprietary seedling             selection of Helleborus hybridus, not patented. -   Propagation:     -   -   Type.—By tissue culture.         -   Time to initiate roots, winter.—About two months at 12° C.         -   Time to produce a rooted young plant, winter.—About six             months at 4° C. to 15° C.         -   Root description.—Thick to thin, fleshy; white to brown in             color.         -   Rooting habit.—Sparse. -   Plant description:     -   -   Plant form and growth habit.—Herbaceous perennial; upright             and mounding plant habit with flowers held just above the             foliar plane; plant shape is ovate; moderately vigorous             growth habit.         -   Plant height.—About 47.6 cm.         -   Plant diameter (area of spread).—About 48.2 cm. -   Foliage description:     -   -   Arrangement.—Leaves arranged in a basal rosette; leaves             palmately compound with about seven leaflets per leaf         -   Leaf length.—About 20 cm.         -   Leaf width.—About 20.7 cm.         -   Leaflet length.—About 11.5 cm.         -   Leaflet width.—About 5.8 cm.         -   Leaf shape.—Palmate; orbicular in outline.         -   Leaflet shape.—Obovate.         -   Leaflet apex.—Broadly acute.         -   Leaflet base.—Cuneate.         -   Leaflet margin.—Sharply serrate; slightly undulate.         -   Leaflet texture, upper and lower surfaces.—Smooth, glabrous;             leathery.         -   Leaflet venation pattern.—Pinnate.         -   Leaflet color.—Developing leaves, upper surface: Close to             137A. Developing leaves, lower surface: Close to 146B. Fully             developed leaves, upper surface: Between 139A and 147A;             venation, close to 144A to 144B, tinged at the base with             close to N186C. Fully developed leaves, lower surface:             Between 146B and 147B; venation, close to 181A.         -   Petiole.—Length: About 17.6 cm. Diameter: About 6 mm.             Texture, upper and lower surfaces: Smooth, glabrous. Color,             upper and lower surfaces: Close to 144A heavily dotted with             close to N186C; at the base, close to 187C. -   Flower description:     -   -   Flower shape and habit.—Single rotate flowers arranged in             terminal and axillary cymes; freely and uniform flowering             habit with about 16 flowers and flower buds developing per             plant; flowers facing outwardly to nodding.         -   Fragrance.—None detected.         -   Natural flowering season.—Plants begin flowering about ten             months after planting; long flowering period, plants flower             from late winter to early spring in Germany.         -   Flower longevity on the plant.—About ten days; flowers not             persistent.         -   Flower buds.—Length: About 1.5 cm. Diameter: About 1 cm.             Shape: Ovate. Color: Close to 145C.         -   Inflorescence height.—About 10.7 cm.         -   Inflorescence diameter.—About 16.1 cm.         -   Flower diameter.—About 9 cm.         -   Flower depth (height).—About 2.5 cm.         -   Petals.—Transformed into nectaries.         -   Sepals.—Quantity and arrangement: Five arranged in a single             whorl. Length: About 4.9 cm. Width: About 3.3 cm. Shape:             Ovate to elliptic. Apex: Broadly acute to rounded. Base:             Cuneate. Margin: Entire, undulate. Texture, upper and lower             surfaces: Smooth, glabrous. Color: When opening, upper             surface: Close to NN155B; base, close to 145B. When opening,             lower surface: Close to NN155A; base, close to 145B. Fully             opened, upper and lower surfaces: Close to NN155A;             inconspicuous central band, close to 157C; base, close to             145B. With development, color becomes closer to 145A.         -   Peduncles.—Strength: Moderately strong. Length: About             35.3 cm. Diameter: About 5 mm. Aspect: About 10° from             vertical. Texture: Smooth, glabrous. Color: Close to 144B to             144C slightly dotted with close to N186C.         -   Pedicels.—Strength: Moderately strong. Length: About 2 cm.             Diameter: About 2 mm. Aspect: Erect to about 40° from the             peduncle axis. Texture: Smooth, glabrous. Color: Close to             144C.         -   Reproductive organs.—Stamens: Quantity per flower:             About 100. Filament length: About 2.1 cm. Filament color:             Close to 155C. Anther shape: Reniform. Anther length: About             2 mm. Anther color: Close to 150C. Pollen amount: Scarce.             Pollen color: Close to 4D. Pistils: Quantity per flower:             About five to eight. Pistil length: About 1.4 cm. Stigma             shape: Club-shaped. Stigma color: Close to 150D. Style             length: About 1.3 cm. Style color: Close to 186C to 186D.             Ovary color: Close to 145B. Nectaries (transformed petals):             Quantity per flower: About 13. Length: About 1.2 cm.             Diameter: About 3.5 mm. Shape: Narrow triangular, flattened             tubular. Color: Close to 144C.         -   Seeds and fruits.—Seed and fruit development have not been             observed on plants of the new Helleborus. -   Garden performance: Plants of the new Helleborus have been observed     to have good garden performance and to tolerate rain and wind;     plants of the new Helleborus have been observed to tolerate high     temperatures of about 35° C. and are hardy to USDA Hardiness Zone 5. -   Pathogen & pest resistance: Plants of the new Helleborus have not     been observed to be resistant to pathogens and pests common to     Helleborus plants. 

It is claimed:
 1. A new and distinct Helleborus plant named ‘COSEH 960’ as illustrated and described. 